Not that it's necessarily going to help, but it might be worth keeping an eye on your local Jessops...
Although I was probably incredibly lucky, a little before Christmas, I was in exactly the same situation looking for a used 5D, and being surprised at the prices.
I happened to wander into one of the local Jessop's stores and saw a "manager's special" on a 5D with 24-105 f4 L IS USM priced at around £1400. It (I thought) was quite a good deal, but still over budget. The friendly (and very knowledgeable) assistant did explain that the displayed price was not correct as it needed to be updated. She explained that their manager's specials were often an item bought by a customer then returned within 30 days. It appeared to me that this one had probably been "bought" by someone, used to cover an event, then returned to the shop. It was in mint condition with a couple of thousand actuations, had all the cables, box, unopened CD, and was supplied with the usual 12 month warranty.
They cannot then sell it as new, so reduce the price by I think 20% for 2 weeks. Then by a further 20% for another 2 weeks before moving it to another shop and increasing the price to the original 20% reduction again. It appeared that I'd seen it the day it went to the lower price. So I ended up walking out of the shop with the 5D and my first L lens for £1016.
One thing is for sure - when you do eventually get yourself a 5D, you will not be disappointed - they are awesome!
Good luck.